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authormatthieu castet <castet.matthieu@free.fr>2010-11-16 22:35:16 +0100
committerIngo Molnar <mingo@elte.hu>2010-11-18 13:32:56 +0100
commit84e1c6bb38eb318e456558b610396d9f1afaabf0 (patch)
tree8051a29e2364446dc1e24bbd5f3b7693d1a454fa /include/linux/module.h
parent5bd5a452662bc37c54fb6828db1a3faf87e6511c (diff)
x86: Add RO/NX protection for loadable kernel modules
This patch is a logical extension of the protection provided by CONFIG_DEBUG_RODATA to LKMs. The protection is provided by splitting module_core and module_init into three logical parts each and setting appropriate page access permissions for each individual section: 1. Code: RO+X 2. RO data: RO+NX 3. RW data: RW+NX In order to achieve proper protection, layout_sections() have been modified to align each of the three parts mentioned above onto page boundary. Next, the corresponding page access permissions are set right before successful exit from load_module(). Further, free_module() and sys_init_module have been modified to set module_core and module_init as RW+NX right before calling module_free(). By default, the original section layout and access flags are preserved. When compiled with CONFIG_DEBUG_SET_MODULE_RONX=y, the patch will page-align each group of sections to ensure that each page contains only one type of content and will enforce RO/NX for each group of pages. -v1: Initial proof-of-concept patch. -v2: The patch have been re-written to reduce the number of #ifdefs and to make it architecture-agnostic. Code formatting has also been corrected. -v3: Opportunistic RO/NX protection is now unconditional. Section page-alignment is enabled when CONFIG_DEBUG_RODATA=y. -v4: Removed most macros and improved coding style. -v5: Changed page-alignment and RO/NX section size calculation -v6: Fixed comments. Restricted RO/NX enforcement to x86 only -v7: Introduced CONFIG_DEBUG_SET_MODULE_RONX, added calls to set_all_modules_text_rw() and set_all_modules_text_ro() in ftrace -v8: updated for compatibility with linux 2.6.33-rc5 -v9: coding style fixes -v10: more coding style fixes -v11: minor adjustments for -tip -v12: minor adjustments for v2.6.35-rc2-tip -v13: minor adjustments for v2.6.37-rc1-tip Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com> Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Andi Kleen <ak@muc.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dave Jones <davej@redhat.com> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4CE2F914.9070106@free.fr> [ minor cleanliness edits, -v14: build failure fix ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/module.h')
-rw-r--r--include/linux/module.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/include/linux/module.h b/include/linux/module.h
index b29e7458b96..ddaa689d71b 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -308,6 +308,9 @@ struct module
/* The size of the executable code in each section. */
unsigned int init_text_size, core_text_size;
+ /* Size of RO sections of the module (text+rodata) */
+ unsigned int init_ro_size, core_ro_size;
+
/* Arch-specific module values */
struct mod_arch_specific arch;
@@ -672,7 +675,6 @@ static inline int module_get_iter_tracepoints(struct tracepoint_iter *iter)
{
return 0;
}
-
#endif /* CONFIG_MODULES */
#ifdef CONFIG_SYSFS
@@ -687,6 +689,13 @@ extern int module_sysfs_initialized;
#define __MODULE_STRING(x) __stringify(x)
+#ifdef CONFIG_DEBUG_SET_MODULE_RONX
+extern void set_all_modules_text_rw(void);
+extern void set_all_modules_text_ro(void);
+#else
+static inline void set_all_modules_text_rw(void) { }
+static inline void set_all_modules_text_ro(void) { }
+#endif
#ifdef CONFIG_GENERIC_BUG
void module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *,